Yes, as Hyejeong says, it is most probably a question asked by a Korean of a foreigner residing in a different country. Other scenarios don't seem to make much sense.
And I would guess it is said like 한국(에) 온 적(이) 있어요? (Have you ever been to Korea?).
One could also say 한국(에) 와 본 적(이) 있어요? or 한국에 와 봤어요?